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Coincidence measurements of breakup of6,7Li and9Be incident on various high-Z targets have provided a complete picture of the physical mechanisms triggering breakup. The measurements identify those breakup processes that are fast enough (10-22) to affect

The role of spherical quantum shells in the competition between fusion and quasi-fission is studied for reactions forming heavy elements. Measurements of fission fragment mass distributions for different reactions leading to similar compound nuclei have been made near the fusion barrier. In general, more quasi-fission is observed for reactions with non-magic nuclei. However, the 40Ca+ 208Pb reaction is an exception, showing strong evidence for quasi-fission, though both nuclei are doubly magic. Time-dependent Hartree-Fock calculations predict fast equilibration of N/Z in the two fragments early in the collision. This transfer of nucleons breaks the shell effect, causing this reaction to behave more like a non-magic one in the competition between fusion and quasi-fission. Future measurements of fission in reactions with exotic beams should be able to test this idea with larger N/Z asymmetries.

The effects of nuclear structure can be manifested at three stages of the reaction dynamics: through the effect of channel couplings in overcoming the entrance channel potential barrier; in damping of the relative motion leading to capture; and in diffusion over the potential energy surface resulting in fusion or quasifission outcomes. This sequence of coupled processes offers many and subtle opportunities for nuclear structure to play a role in affecting the dynamics, and thus the outcomes. Recent experimental results, in particular mass-angle distributions (MAD), have isolated different ways in which nuclear structure has been shown to play a significant role in determining reaction outcomes.

Using a back-angle detector array covering 117° to 167°, coincidence measurements of breakup fragments at sub-barrier energies have enabled the complete characterisation of the breakup processes in the reactions of 6,7Li with 208Pb. Those breakup proces

The SOLEROO (solenoidal exotic rare isotope) separator is under development for the production of light radioactive ion beams at the Australian National University. The separator is based on a single superconducting solenoid followed by two tracking detectors. Cross-section and beam purity measurements have been made to optimise the production of 6He, 8Li, 10Be and 12B beams. Having validated the trajectory simulation code SoliX, the optimal geometry for utilisation of the tracking detectors has also been explored.

The reaction 16O + 208Pb is a benchmark in nuclear reaction studies as it involves two doubly magic nuclei. New measurements of back-scattered projectile-like fragments at sub-barrier energies show that the probability of two-proton (2p) transfer is much

Below-barrier no-capture breakup measurements of the weakly bound Be9 nucleus, incident on targets ranging in atomic number from 62 to 83, have been carried out using a large-area high-resolution back-angle detector array. It is shown that the three-body

The above-barrier suppression of complete fusion in reactions with weakly bound stable nuclei displays a strong correlation with their breakup threshold. Simplistically, this observation suggests that suppression of complete fusion is due to the direct breakup of the weakly bound partner, prior to reaching the barrier. However, new measurements of breakup at energies below the fusion barrier show that breakup following transfer, rather than direct breakup, is the dominant mechanism. The insights into the physical mechanisms of breakup from these measurements, in conjunction with theoretical developments, are being used to obtain an understanding of the relationship between sub-barrier breakup and suppression of complete fusion.

The coupled channels model has generally been very successful in describing the different reaction outcomes following the collision of heavy nuclei. However, several outstanding problems remain - amongst them the inability to simultaneously describe elastic scattering and fusion data, and more recently the failure to consistently describe deep-sub barrier and above-barrier fusion. Possible reasons include deviation of the nuclear potential from the assumed Woods-Saxon form, and the emergence of processes which cannot be described within the coherent coupled channels framework. The question is whether there are inadequacies in the current models which need to be addressed before we can hope to get a consistent description of the main reaction processes. We put forward the possibility that dissipation near the fusion barrier and the consequent loss of coherence need to be considered for a realistic description of nuclear collisions.